Distributed on-demand media transcoding system and method

ABSTRACT

A system and method for the on-demand transcoding of media content from a source type to a destination type is provided, wherein the system includes a plurality of transcoders for transcoding from a plurality of source types to a plurality of destination types, and wherein the system receives a transcoding request for media content, fetches the media content in response to the transcoding request, sends the media content to one of the plurality of transcoders based on the source type and destination type, transcodes the media content from the source type to the destination type, thereby generating transcoded media content, and transmits the transcoded media content. The system fetches, sends, and transcodes the media content and transmits the transcoded media content in a pipelined fashion. The system also provides for the publication of media content as a file or stream of digital data, for the archiving of media content, and the caching of transcoded media content to improve system efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/141,966, filed May 10, 2002, now U.S. Pat. No. 6,593,860 which is acontinuation of U.S. application Ser. No. 09/742,294, filed Dec. 22,2000, now U.S. Pat. No. 6,407,680.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and method for transcodinginformation. More specifically, the present invention relates to asystem and method for transcoding media content.

2. Related Art

The rapid publication of media content has been sought throughout humanhistory. Publishers strive to deliver media content faster to largeraudiences. As used herein, the term “media content” refers to anyinformation, including audio, video, data, ideas, images, story, sound,text, or other content, that is perceived by one or more human senses.

The digital representation of media content combined with computing andnetworking technologies now provide a powerful way to publish. Accordingto this new mode of publishing, networking technology permits thedelivery of digitized media content over a network to end usercomputers. Communication protocols define how the digitized mediacontent is exchanged over the network. A media player runs on the enduser computer to allow the user to play or otherwise experience themedia content.

Digital representations of media content come in different types. Thesetypes are generally defined according to a series of publishingvariables which can include, but are not limited to, the file format,bit rate, communication protocol(s), physical medium, compressionalgorithm, and/or digital rights management information associated withthe media content. The type of digitized media content which is usedwill depend upon a number of factors, such as, the computing and/ornetworking technology used in the process of publishing and the natureof the content itself.

For example, many types of digitized media content are defined accordingto a file format. Common file formats include QUICK TIME, MPEG, AVI,MP3, REAL, WINDOWS MEDIA, H.263 video coding, and PALM-compatibleformats. A format can define media content as a file or in a datastream. See, for example, the graphics file formats and other formatsdescribed by J. D. Murray and W. vanRyper, The Encyclopedia of GraphicsFile Formats, Second Edition (O'Reilly & Associates, Inc.: Sebastopol,Calif.), 1996, which is incorporated in its entirety herein byreference.

Digitized media content types can also be categorized according to thetype of encoding or compression technique that is used to reduce thephysical size of the media content, or according to the type of physicalmedium that supports the storage of the media content. Different kindsof physical medium are used in publishing media content, such asmagnetic or optical storage devices, memory devices, and wirelessmediums.

Digitized media content types may also be categorized by the type ofcommunication protocol or protocols used to transmit the media content.In packet-switched networks such as the Internet, many layers ofprotocols are used. Such protocols can include network and transportprotocols and application protocols. Network and transport protocols arein part responsible for delivering packets of digital data. Examples ofnetwork and transport protocols are Internet Protocol (IP), TransmissionControl Protocol (TCP), User Datagram Protocol (UDP), and Real-TimeTransport Protocol (RTP). Application protocols are higher levelprotocols that run on top of the network and transport protocols. Amongother things, application protocols provide services that supportdigital media publishing. Examples of application protocols used inWorld Wide Web technology are HyperText Transport Protocol (HTTP) andReal-Time Streaming Protocol (RTSP).

The emergence of a fast-growing number of media players has created awidening gap between the richness of the various types of media contentand the diverse capabilities of the client devices to handle thecontent. As a result, the technology selection process for the end userhas become quite complicated. For example, the user often cannot becertain that a given media player will be able to play the type of mediacontent in which he or she is interested. Also, the user may be requiredto frequently download new media playing software in order to accessdesired content.

Furthermore, because users employ a wide variety of client mediaplayers, content providers are required to publish original mediacontent in a number of source types in order to deliver the content to alarge number of users. Content providers with archived media contentalso face a burden of having to publish archived media content into newor updated source types.

Transcoders convert certain types of media content (source type) toanother type of media content (destination type). This conversion isknown as “transcoding.” Transcoding can involve a number of differentconversion operations. The particular conversion operations used dependupon what publishing variables are being converted. For example,transcoding can involve a conversion operation from one encoded dataformat to another encoded data format (such as, converting CCITT Group 3encoded data to RLE-encoded data.) See, Murray and vanRyper, p. 1095.

Conventional multi-type transcoding services are provided off-line,before the content provider publishes media content, adding anundesirable and unavoidable delay to the publishing process. Althougharrangements for the real-time transcoding of media content are known,(e.g., transcoding and delivery of live media events over the Internet),these arrangements are limited in that they only allow for media contentto be transcoded into a single destination type, and do not permit forthe delivery of media content in multiple destination types.

Also, because off-line multi-format transcoding services are expensive,content providers can only afford to have their media content transcodedinto a limited number of destination types. Users with media playersincapable of accommodating the destination type of the transcoded filessimply cannot access the content. Accordingly, conventional mediaproduction is limited to a “push” process in which content providers areforced to speculate about which media player users will employ to playtheir media files.

As a further result of this rapid development in media publishingtechnology, new internet and wireless device manufacturers must alsoinvest heavily in the transcoding of media content so that a variety ofcontent can be experienced on new media playing devices as newdestination types. Thus, new internet and wireless device manufacturersexperience the same setbacks and disadvantages from conventionaltranscoding schemes as described above.

SUMMARY OF THE INVENTION

The present invention is directed to a system and method for theon-demand transcoding of media content into from a plurality of sourcetypes to a plurality of destination types. In one embodiment, a methodis provided for transcoding media content from a source type to adestination type, comprising the steps of receiving a transcodingrequest for the media content, fetching the media content, selecting oneof a plurality of transcoders for transcoding from a plurality of sourcetypes to a plurality of destination types based on the source type andthe destination type, sending the media content to the selectedtranscoder, transcoding the media content from the source type to thedestination type, thereby generating a transcoded media file, andtransmitting the transcoded media content.

In embodiments of the present invention, the media content may compriseeither a file of digital information or a stream of digital data. Inembodiments of the present invention, the media content is fetched, sentand transcoded as a stream of digital data, the transcoded media file istransmitted as a stream of digital data, and the fetching, sending,transcoding and transmitting are all performed in a pipelined fashion.

In embodiments of the present invention, the transcoding request isreceived over the Internet and the transcoded media content istransmitted over the Internet.

In embodiments of the present invention, the media content type isdefined according to at least one publishing variable, wherein thepublishing variable may be the file format of the media content, thebit-rate of the media content, the compression algorithm according towhich the media content is stored, the communication protocol accordingto which the media content is transferred, or the physical medium onwhich the media content is stored, and the step of transcoding the mediacontent comprises converting the publishing variable of the mediacontent from a source publishing variable type to a destinationpublishing variable type.

A media transcoding system in accordance with the present inventiontranscodes media content from a source type to a destination type. Themedia transcoding system includes a network interface, a resourcemanager, a transmitting server, a streaming server, and a plurality oftranscoders for transcoding from a plurality of source types to aplurality of destination types. The network interface is adapted toreceive a transcoding request for the media content. The resourcemanager is adapted to respond to the transcoding request and, inresponse to the transcoding request, to command the transcoding serverto fetch the media content, to select one of the plurality oftranscoders based on the source type and the destination type, tocommand the selected transcoder to transcode the media content from thesource type to the destination type, thereby generating transcoded mediacontent, and to command the streaming server to transmit the transcodedmedia content.

In embodiments of the present invention, the media content may comprisea file of digital information or a stream of digital data.

In embodiments of the present invention, the transmitting server isadapted to fetch the media content as a data stream, the selectedtranscoder is adapted to transcode the media content as a data stream,and the streaming server is adapted to transmit the transcoded mediacontent as a data stream. The resource manager manages the operation ofthe transmitting server, the selected transcoder, and the streamingserver so that the fetching, transcoding and transmitting occur in apipelined fashion.

In embodiments of the present invention, the network interface isadapted to receive the transcoding request over the Internet and thestreaming server is adapted to transmit the transcoded media contentover the Internet.

In embodiments of the present invention, the media content type isdefined according to at least one publishing variable, wherein thepublishing variable may be the file format of the media content, thebit-rate of the media content, the compression algorithm according towhich the media content is stored, the communication protocol accordingto which the media content is transferred, or the physical medium onwhich the media content is stored, and the selected transcoder isadapted to convert the publishing variable of the media content from asource publishing variable type to a destination publishing variabletype.

The invention is advantageous in that it permits the transcoding ofmedia content on demand from a single source type to a variety ofdestination types in a manner that is transparent to the contentprovider and the user.

The invention is also advantageous in that it permits the transcoding ofmedia content stored in files on demand from a single source type to avariety of destination types in a manner that is transparent to thecontent provider and the user.

Another advantage of the invention is that it permits the transcoding oflive (i.e., streaming) media content on demand from a single source typeto a variety of destination types in a manner that is transparent to thecontent provider and the user.

Another benefit of the invention is that it permits a user to playvarious types of media content regardless of the media player employedby the user.

Yet another benefit of the invention is that it obviates the need for auser to download a newer media player or upgrade an existing mediaplayer in order to access desired media content.

A further advantage of the invention is that it permits a contentprovider to provide original media content in a single source type to alarge number of users using diverse media players that accept differentmedia content types.

A further benefit of the invention is that it expedites the publishingprocess for media content providers by allowing them to publish mediacontent without first employing off-line encoding services. Theinvention thus minimizes the time-to-market for the publication of mediacontent.

Another benefit of the invention is that it creates a lower barrier ofentry to media publication by permitting content providers to out-sourcenecessary transcoding tasks and to avoid investment in transcodingservers and other equipment necessary for transcoding.

Yet another benefit of the invention is that it permits contentproviders to deliver media content to users with media players incapableof accommodating the source type of the original media content.

A further advantage of the invention is that it defers the transcodingof media content until the content is demanded by a user for a specificmedia player. Accordingly, content providers can avoid an unnecessaryinvestment in the transcoding of original media content to types notrequested by users.

Additional features and advantages of the invention will be set forth inthe description that follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the system and method particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate the present invention and, togetherwith the description, further serve to explain the principles of theinvention and to enable a person skilled in the pertinent art to makeand use the invention.

In the drawings:

FIG. 1 is a block diagram of a media transcoding system according to oneembodiment of the present invention.

FIG. 2 is a block diagram of an example media transcoding engineaccording to one embodiment of the present invention.

FIG. 3 is a flowchart that describes a routine for publishing mediacontent according to an embodiment of the present invention.

FIG. 4 is a flowchart that describes a routine for publishing mediacontent according to an embodiment of the present invention.

FIGS. 5A-5B are a flowchart that describes a routine for accessing mediacontent according to an embodiment of the present invention.

FIG. 6 depicts an exemplary transcoder that may be used in accordancewith embodiments of the present invention.

FIG. 7 is a table showing exemplary transcoding source types anddestination types for various publishing variables according to anembodiment of the present invention.

The present invention will now be described with reference to theaccompanying drawings. In the drawings, like reference numbers indicateidentical or functionally similar elements. Additionally, the left-mostdigit(s) of a reference number identifies the drawing in which thereference number first appears.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Table of Contents

-   A. Overview of the Invention-   B. Operating Environment-   C. Media Transcoding Engine of the Present Invention-   D. Publishing of Media Content According to Embodiments of the    Present Invention-   E. Accessing Media Content According to Embodiments of the Present    Invention-   F. Further Transcoder Operation and Media Content Examples-   G. Alternate Embodiments of the Present Invention-   H. Conclusion    A. Overview of the Invention

The present invention is directed to a system and method for theon-demand transcoding of media information from a variety of sourcetypes into a variety of destination types. According to the presentinvention, in a system comprising a plurality of transcoders fortranscoding from a plurality of source types to a plurality ofdestination types, a method is provided for transcoding media contentfrom a source type to a destination type. The method includes receivinga transcoding request for the media content, fetching the media content,and sending the media content to a selected one of the plurality oftranscoders. The transcoder is selected based on the source type and thedestination type. The transcoder transcodes the media content from thesource type to the destination type, thereby generating transcoded mediacontent. The transcoded media content is then transmitted.

A media transcoding system in accordance with the present inventiontranscodes media content from a source type to a destination type. Thetranscoding system includes a network interface, a resource manager, atransmitting server, a streaming server, and a plurality of transcodersfor transcoding from a plurality of source types to a plurality ofdestination types. The network interface receives a transcoding requestfor media content. The resource manager commands the transmitting serverto fetch the media content. The resource manager further selects one ofthe plurality of transcoders based on the source type and destinationtype, and commands the selected transcoder to transcode the mediacontent from the source type to the destination type to generatetranscoded media content. The resource manager also commands thestreaming server to transmit the transcoded media content.

The invention will now be further described with reference to FIGS. 1-7.

B. Operating Environment

FIG. 1 is a block diagram representing an example operating environment100 of the transcoding system of the present invention. It should beunderstood that the example operating environment 100 is shown forillustrative purposes only and does not limit the invention. Otherimplementations of the operating environment described herein will beapparent to persons skilled in the relevant art(s) based on theteachings contained herein, and the invention is directed to such otherimplementations.

Referring to FIG. 1, example operating environment 100 includes a viewerclient 102, a content provider client 104, a media transcoding engine106, and a network 108. Only one viewer client 102 and content providerclient 104 is shown for clarity. In general, any number of thesecomponents can be included in the transcoding system of the presentinvention.

The viewer client 102, the content provider client 104 and the mediatranscoding engine 106 are all connected via a network 108. The network108 connects all the components of the present invention, and can be anytype of computer network or combination of networks including, but notlimited to, circuit switched and/or packet switched networks, as well aswireless networks. In one example, the network 108 includes theInternet.

Any conventional communication protocol can be used to supportcommunication between the components of the transcoding system 100. Forexample, a Transmission Control Protocol/Internet Protocol (TCP/IP)suite can be used to establish links and transport data and Real-TimeStreaming Protocol (RTSP) can be used to stream data between componentsof the transcoding system 100. A World Wide Web-based application layerand browser (and Web server) can also be used to further facilitatecommunication between the components shown in FIG. 1. However, theseexamples are illustrative. The present invention is not intended to belimited to a specific communication protocol or application, and otherproprietary or non-proprietary network communication protocols andapplications can be used.

The viewer client 102 is used by a user, or viewer, to request andreceive media content via the network 108, and to play received mediacontent. In embodiments, the viewer client 102 is a personal computerthat includes a Web browser and one or more media players running underthe computer operating system. Alternately, the viewer client 102 can bea WEBTV, a WINDOWS CE device, a Personal Digital Assistant (PDA), a PALMhandheld device, a console appliance with network access capability, anMP3 appliance, or any other client device and/or program capable ofrequesting, receiving and playing media content. However, the inventionis not limited to these examples, and one skilled in the art willappreciate that a wide variety of client devices and programs can beused to request, receive and play media content via the network 108. Theinvention is directed to such other client devices and programs.

The viewer client 102 is capable of receiving and playing various typesof media content. For example, the viewer client may receive and playmedia content in various well-known encoded formats including, but notlimited to, MPEG, AVI, MP3, REAL, WINDOWS MEDIA, QUICK TIME, H.263 videocoding, and PALM-compatible formats.

The content provider client 104 is used by the content provider topublish and/or transmit media content over the network 108. Inembodiments, the content provider client 104 includes a clientworkstation and media input device and/or program. For example, thecontent provider client 104 may comprise a personal computer with anattached media input device. The content provider client 104 can providemedia content using a variety of media input devices and programs. Forexample, media content can be provided using cameras (8 mm, Hi-8, or anyvideo digitizing device), line-in/microphone (either attached to any ofthe camera devices, or stand-alone audio input devices), digitalcameras, devices that upload slide shows with voice-over illustrations,files previously encoded in a client-chosen format, or files availablevia a network accessible mount point (such as, but not limited to,Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), orremote servers). These examples are not limiting, and one skilled in theart will appreciate that a wide variety of client devices and programscan be used to publish and/or transmit media content via the network108, and that the invention is directed to such client devices andprograms.

The content provider client 104 is capable of publishing and/ortransmitting various types of media content. For example, the contentprovider client 104 can provide multimedia files in various well-knownencoded formats including, but not limited to, MPEG, AVI, MP3, REAL,WINDOWS MEDIA, QUICK TIME, H.263 video coding, and PALM-compatibleformats.

The media transcoding engine 106 acts as an intermediate between thecontent provider client 104 and the viewer client 102. As will bedescribed in more detail below, the media transcoding engine 106receives requests for media content from the viewer client 102 andobtains the requested media content from the content provider client104. The media transcoding engine 106 then transcodes the media contentreceived from the content provider client 104 from a source type to adestination type that can be accommodated by the viewer client 102 anddelivers the transcoded media content to the viewer client 102. Themedia transcoding engine 106 performs the transcoding and delivery ofthe requested media content on-demand in a manner that is transparent tothe content provider as well as the viewer of the media content.

In accordance with the present invention, because the media transcodingengine 106 can transcode media content into a variety of destinationtypes, the content provider can provide media content using a singlemedia input device and still deliver the content to viewers using avariety of different media players, each of which requires a differentdestination type. Additionally, the present invention permits users toaccess a variety of media content published in different source types nomatter what media player they are using. The media transcoding engine106 of FIG. 1 will now be described in more detail.

C. Media Transcoding Engine of the Present Invention

FIG. 2 is a block diagram of the media transcoding engine 106 accordingto an embodiment of the present invention. The media transcoding engine106 is comprised of a number of components including a viewer Web serverinterface 202, a content provider Web server interface 204, a taskmanager 206, a resource manager 208, a database 210, a transcoded cache212, a master archive 214, a machine farm 216, and, within the machinefarm 216, transcoder servers 218, transmitter servers 220, and streamingservers 222. The components of the media transcoding engine 106 are eachoperably connected to each other by an internal computer networkrepresented, in part, by the arrows connecting the components in FIG. 2.The computer network can include one or more computer buses forconnecting components co-existing on the same server, as well as anyother type of communication infrastructure for connecting remotecomponents including, but not limited to, circuit switched and/or packetswitched networks, as well as wireless networks. In embodiments, thenetwork connecting the components within the media transcoding engine106 includes a local area network (LAN).

Each of the components of the media transcoding engine 106 will now bedescribed.

The content provider Web server interface 204 is a network interfacebetween the media transcoding engine 106 and the content provider client104 that permits a content provider to publish media content. Thecontent provider Web server interface 204 receives and processes arequest to publish media content from the content provider client 104.In embodiments, the content provider Web server interface 204 alsoreceives the media content itself from the content provider client 104for archival purposes within the media transcoding engine 106.Alternately, the content provider Web server interface 204 receiveslocation and access information from the content provider client 104,which permits the media transcoding engine 106 to locate and fetch themedia content at a later time for transcoding and/or delivery of themedia content to a viewer.

In embodiments, the content provider can download a software tool or“plug-in” from the content provider Web server interface 204 thatfacilitates the delivery of media content from the content providerclient 104 to the content provider Web server interface 204. The toolprovides a configurable interface that resides on the content providerclient 104 and permits the content provider to upload various types ofmedia content to the content provider Web server interface 204.

After it receives the media content, or, alternately, the necessarylocation and access information for fetching the media content, thecontent provider Web server interface 204 returns address and sourceinformation to the content provider client 104. The address informationpoints viewers who request the content provider's media content to themedia transcoding engine 106 and the source information providesinformation concerning the source of the requested media content. Asshown in FIG. 2, in embodiments of the present invention, the addressand source information comprise a URL (Uniform Resource Locator) thatpoints the viewer client to the media transcoding engine 106 andprovides information to the media transcoding engine 106 about thesource of the requested media content. Content providers can post theURL as a link on their Web-site, thereby allowing viewers who visittheir Web-site to click on the URL in order to access the media contentvia the media transcoding engine 106.

The viewer Web server interface 202 is a network interface between themedia transcoding engine 106 and the viewer client 102 that permitsmedia content to be requested by and delivered to a viewer. The viewerWeb server interface 202 receives and processes a request to accessmedia content from the viewer client 102, thereby initiating thetranscoding and delivery of the requested media content to the viewerclient 102. Because transcoded media content is streamed to the viewerclient 102 by a streaming server and/or proxy server as will bediscussed in more detail herein, the viewer Web server interface 202sends a reply to the viewer client 102 redirecting the viewer client 102to the appropriate server from which to receive the requested mediacontent.

The media transcoding engine 106 is adapted to deliver requested mediacontent to the viewer client 102 in an optimal destination type. Theoptimal destination type for the viewer client 102 may be determined ina number of ways.

In embodiments, the viewer can download a software tool or “plug-in”from the viewer Web server interface 202 that facilitates the deliveryof media content from the media transcoding engine 106 to the viewerclient 102. The tool is a program that runs on the viewer client 102 andassists in determining the optimal destination type for the viewerclient 102 to receive and play media content. In embodiments, theoptimal destination type may be determined either by automatic tests runon the viewer client 102, or by requiring the viewer to provide systemand preference information explicitly. The optimal destination type maythen be stored by the software tool as a “cookie” on the viewer client102 for future reference by the media transcoding engine 106.

Alternatively, the optimal destination type may be stored in a databasewithin the media transcoding engine 106, and a “cookie” may be stored onthe viewer client 102 that simply identifies the user. Then, when themedia transcoding engine 106 is required to transcode media content fordelivery the viewer client 102, it may read the cookie and map theidentification of the user to the database to obtain the optimaldestination type.

In further embodiments, the optimal configuration can be made adjustablefor more sophisticated users, or may be updated periodically in case ofnetwork condition changes between the viewer client 102 and the network108 (e.g., change of Internet Service Provider, or change of connectionspeed).

As described above, the content provider Web server interface 204 andthe viewer Web server interface 202 each comprise network interfaces. Inembodiments, the content provider Web server interface 204 and theviewer Web server interface 202 each comprise a Web server. In alternateembodiments, the content provider Web server interface 204 and theviewer Web server interface 202 each comprise a load-balancer thatredirects requests to other physical Web servers (in other words, theyare virtual Web servers).

The task manager 206 is a component of the media transcoding engine 106that processes requests for media content received from the viewer Webserver interface 202. The task manager determines whether the mediatranscoding engine 106 has all the information necessary to deliver therequested media content, gathers any missing information, and determineswhat tasks need to be executed to deliver the requested media content.The task manager then interacts with the resource manager 208 to executethe required tasks.

The resource manager 208 is a program that determines what resources areavailable within the media transcoding engine 106 to carry out the tasksnecessary to deliver the requested media content (e.g., fetching andtranscoding the requested media content), allocates the necessary tasksto the appropriate resources, and then manages the tasks to completion.In a sense, the resource manager 208 works like a traditional loadbalancer. However, whereas a traditional load balancer operates bymanaging a virtual machine consisting of a set of machines that performseparate and identical tasks, the resource manager distributes tasksthat are often different and interdependent. The process by which theresource manager 208 distributes tasks and allocates resources will bedescribed in more detail below.

Although FIG. 2 shows only one resource manager 208, it will beunderstood by one of ordinary skill in the relevant art(s) thatalternate embodiments of the media transcoding engine 106 can includemore than one resource manager for allocating tasks and resources withinthe media transcoding engine 106.

In embodiments, the task manager 206 and the resource manager 208 may beimplemented as software running on one or more general purpose server(s)within the media transcoding engine 106.

The machine farm 216 includes a plurality of individual servers forperforming the transcoding and delivery of requested media contentwithin the media transcoding engine 106. The machine farm 216 includestransmitter servers 220 that fetch the source data for the requestedmedia content, transcoder servers 218 that transcode the source data tothe appropriate destination type, and streaming servers 222 that streamthe transcoded media content to the viewer client 102 or to a proxyserver for delivery to the viewer client 102.

The transmitter servers 220 run transmitter software that permits themto fetch the requested media content from a source location and transmitit to one of the transcoder servers 218, streaming servers 222, or aproxy server (not shown).

The transcoder servers 218 run transcoder software that permit them totranscode from a variety of known source types to a variety of knowndestination types. In embodiments, the machine farm 216 is implementedutilizing a plug-in architecture that permits new transcoding servicesto be added incrementally, thereby ensuring that the media transcodingengine 106 can accommodate new media types.

In alternate embodiments of the present invention, a single server mayperform both the transmitter and transcoder functions. In furtheralternate embodiments, the transmitting of requested media content maybe carried out by software external to the media transcoding engine 106.For example, the transmitting of requested media content may be executedby software residing on the content provider client 104.

In embodiments, each streaming server within the machine farm 216 is atype-specific streaming server dedicated to the delivery of mediacontent of a single type. For example, a streaming server within themachine farm 216 may be dedicated to delivering transcoded media contentin REAL format, WINDOWS MEDIA format, QUICK TIME format, etc. Thestreaming servers 222 within the machine farm may run off-the-shelfindustry-standard streaming server programs, streaming server programsthat are implemented according to a public standard, or proprietarystreaming server programs.

In addition to streaming media content to the viewer client 102, thestreaming servers 222 keep usage statistics pertaining to the mediacontent being delivered as well as the destination types in which themedia content is being delivered. The streaming servers 222 provide theusage statistics to the resource manager 208, thereby permitting theresource manager 208 to perform cache management functions within themedia transcoding engine 106. For example, such usage statistics permitthe resource manager 208 to cache the most frequently requestedtranscoded media content in the most frequently requested destinationtypes. The caching of transcoded media content will be further describedin regard to the transcoded cache 212, below.

In alternate embodiments, the tracking of usage statistics is carriedout by an optional proxy server (not shown) that channels streamingmedia content from the streaming servers 222 to the viewer client 102.Such an implementation may be desired where the streaming servers 222are not capable of tracking usage statistics.

As shown in FIG. 2, each server within the machine farm 216 includes aslave monitor that serves as an interface between the server and theresource manager 208. The slave monitor operates to receive tasks fromthe resource manager 208, to initialize the tasks within the server, andto report the status of initialized tasks, including the reporting ofthe failure or completion of an assigned task. By reporting the statusof each task within a server, the slave monitor thereby permits theresource manager 208 to manage the execution of all the tasks within themedia transcoding engine 106.

In an alternate embodiment, the slave monitor only initiates tasksreceived from the resource manager 208, and the tasks themselves reportdirectly to the resource manager 208 rather than to the slave monitor.

The database 210 is used by the resource manager 208 to assist inmanaging tasks and resources within the media transcoding engine 106.The database 210 stores information concerning the status of each activeand pending task as well as information concerning the status of eachresource within the machine farm 216, thereby aiding the resourcemanager 208 in determining which resources are currently available tothe resource manager 208 for executing necessary tasks.

The database 210 is also used by the task manager 206 to keep track ofpublished media content archived within the media transcoding engine106. The database 210 maintains source information about such publishedmedia content including the identity, source location, and source typeof the media content, when available.

The database 210 can be implemented using any type of database structureknown in the art for storing data, including, but not limited to,relational databases, object-oriented databases, flat-file databases orinverted-list databases. In embodiments, the database 210 can be storedon one or more general purpose servers, file servers, or networkattached storage appliances internal to the media transcoding engine106.

The master archive 214 is an archive within the media transcoding engine106 that stores the original media content published by the contentprovider and received by the content provider Web server interface 204from the content provider client 104. Also, where the media transcodingengine 106 is required to fetch original media content from a locationoutside the media transcoding engine 106, the media transcoding engine106 can cache a copy of the original media content in the master archive214. By caching a copy of the original media content in the masterarchive 214, the media transcoding engine 106 avoids having to fetch theoriginal media content from outside the internal network of the enginewhen a subsequent request for the same media content is received.

The transcoded cache 212 is a cache within media transcoding engine 106.The transcoded cache 212 is used by the media transcoding engine 106 tostore a copy of requested media content after it has been transcoded.When subsequent requests are received for the same media content in thesame destination type, the media transcoding engine 106 delivers thecontent from the transcoded cache, thereby avoiding the expensive CPUoverhead of repeatedly transcoding the same media content.

The resource manager 208 keeps track of what is cached within the masterarchive 214 and the transcoded cache 212 and manages the utilization ofeach cache using intelligent algorithms. In embodiments, the intelligentalgorithm used by the resource manager 208 to manage the utilization ofeach cache is based on usage statistics received from the streamingservers 222 and/or optional proxy servers (not shown), as discussedabove, regarding the frequency with which media content is requested invarious destination types. For example, in embodiments, the resourcemanager 208 uses a Least-Recently-Used algorithm to determine whether acertain copy of media content should be retained within a cache ordiscarded. According to a Least-Recently-Used algorithm, a copy of mediacontent is discarded if it has not met a predetermined threshold for anumber of accesses in a given time. This example is not limiting and oneskilled in the relevant art(s) will appreciate that any number ofintelligent algorithms known in the art may be used to manage theutilization of the master archive 214 and the transcoded cache 212. Suchintelligent algorithms are within the scope and spirit of the presentinvention.

In embodiments, the master archive 214 and/or the transcoded cache 212are implemented as one or more network attached storage appliancescoupled to the internal network within the media transcoding engine 106.However, the invention is not so limited, and any suitable storagedevice may be used to implement the master archive 214 and/or thetranscoded cache 212, including but not limited to, general-purposeservers running caching software, file servers, one or more disk arrays,or a storage area network (SAN).

The methods by which media content is published and accessed accordingto embodiments of the present invention will now be described.

D. Publishing of Media Content According to Embodiments of the PresentInvention

In embodiments of the present invention, media content may be publishedeither as an encoded file or delivered as a continuous stream of data,as in the case of a live audio or video feed.

FIG. 3 depicts a flowchart 300 of a method by which media content ispublished according to embodiments of the present invention wherein themedia content is an encoded media file. The invention, however, is notlimited to the description provided by the flowchart 300. Rather, itwill be apparent to persons skilled in the art from the teachings hereinthat other functional flows are within the scope and spirit of thepresent invention.

In step 302, the content provider sends a request to publish contentfrom the content provider client 104 to the content provider Web serverinterface 204. In embodiments, the request comprises an HTTP request.

In step 304, the content provider Web Server interface 204 sends aprompt to the content provider client 104 asking for the media contentitself or the necessary location and access information to fetch themedia content. As discussed above, according to embodiments of thepresent invention, the content provider can either archive media contentwithin the media transcoding engine 106, or can store media content inan alternate location outside of the media transcoding engine 106, suchas on the content provider's own server.

As shown in step 306, where the content provider wishes to store theencoded media file in an archive within the media transcoding engine106, the content provider delivers the media file to the contentprovider Web server interface 204 via the content provider client 104.At step 308, after the content provider Web server interface 204receives the encoded media file, it transmits the file to the masterarchive 214 for archival within the media transcoding engine 106. Fromthe master archive 214, the encoded file is available to the resourcemanager 208 and other components of the media transcoding engine 106. Atstep 310, the identity and location of the archived file is reported bythe content provider Web-Server interface 204 to the task manager 206,which stores the information within the database 210 for futurereference. In embodiments, the source type of the archived file is alsostored within the database 210 for future reference.

As shown in step 312, where the content provider wishes to store theencoded media file in an alternate location outside of the mediatranscoding engine 106, the content provider provides the location andaccess information necessary to fetch the encoded media file to thecontent provider Web server interface 204 via the content providerclient 104.

At step 316, after receiving either the encoded media file or thelocation and access information necessary to fetch the encoded mediafile, the content provider Web server interface 204 provides the contentprovider client 104 with address and source information. The addressinformation points viewers who request the content provider's mediacontent to the media transcoding engine 106 and the source informationprovides information concerning the source of the requested mediacontent. Where the encoded media file is stored in an alternate locationoutside of the media transcoding engine 106, the source informationincludes the location and access information provided by the contentprovider in earlier step 312.

In embodiments, the address and source information comprises a URL(Uniform Resource Locator) that points the viewer client 102 to themedia transcoding engine 106 and provides information to the mediatranscoding engine 106 about the source of the requested media content.Content providers can post the URL as a link on their web-site, therebyallowing viewers who visit their web-site to click on the URL in orderto access the media content via the media transcoding engine 106.

After step 316, the flowchart 300 ends.

FIG. 4 depicts a flowchart 400 of a method by which media content ispublished according to embodiments of the present invention wherein themedia content is delivered as a continuous stream of data, as in thecase of a live audio or video feed. The invention, however, is notlimited to the description provided by the flowchart 400. Rather, itwill be apparent to persons skilled in the art from the teachings hereinthat other functional flows are within the scope and spirit of thepresent invention.

In step 402, the content provider sends a request to publish streamingmedia content from the content provider client 104 to the contentprovider Web server interface 204. In embodiments, the request comprisesan HTTP request.

In step 404, the content provider Web Server interface 204 sends aprompt to the content provider client 104 asking for the streaming mediacontent.

As shown in step 406, the content provider continuously streams themedia content to the content provider Web server interface 204 via thecontent provider client 104.

At step 410, after receiving the streaming media content, the contentprovider Web server interface 204 provides the content provider client104 with address and source information. The address information pointsviewers who request the content provider's media content to the mediatranscoding engine 106 and the source information provides informationconcerning the source of the requested media content. In embodiments,the address and source information comprises a URL (Uniform ResourceLocator) that points the viewer client 102 to the media transcodingengine 106 and provides information to the media transcoding engine 106about the source of the requested media content. Content providers canpost the URL as a link on their web-site, thereby allowing viewers whovisit their web-site to click on the URL in order to access the mediacontent via the media transcoding engine 106.

After step 410, the flowchart 400 ends.

Methods by which published media content is accessed by a vieweraccording to embodiments of the present invention will now be described.

E. Accessing Media Content According to Embodiments of the PresentInvention

As described herein, embodiments of the present invention perform thetranscoding of media content on demand, in response to a viewer'srequest to access media content. Additionally, embodiments of thepresent invention essentially perform the transcoding of media contentin “real-time” after the publication of the media content, as part ofthe media content delivery process. In particular embodiments of thepresent invention, the delay between the submission of a request to viewmedia content to the media transcoding engine 106 and the delivery ofthe media content to the viewer client 102 will be approximately thirtyseconds or less. However, the invention is not limited to a specificdelivery time and can encompass a variety of delivery times greater thanor less than thirty seconds.

FIG. 5 depicts a flowchart 500 of a method by which media content isaccessed by a viewer according to embodiments of the present invention.The invention, however, is not limited to the description provided bythe flowchart 500. Rather, it will be apparent to persons skilled in theart from the teachings herein that other functional flows are within thescope and the spirit of the present invention.

In step 502, the viewer sends a request to access media content via theviewer client 102 to the viewer Web server interface 202 within themedia transcoding engine 106. In embodiments, the request is an HTTPrequest generated by the viewer client 102 when the viewer clicks on aURL on the content provider's web-site. As discussed above, the URLlink, which may be provided by the media transcoding engine 106 to thecontent provider during the media content publishing process, containsaddress information and source information that points the viewer client102 to the media transcoding engine 106 and provides information to themedia transcoding engine 106 about the source of the requested mediacontent.

After the viewer Web server interface 202 receives the request, itforwards it to the task manager 206.

In step 504, the task manager 206 parses the request to determine if thenecessary request information is included in order to service therequest. In embodiments of the invention where the request comprises anHTTP request, the task manager 206 parses the header of the HTTP requestto determine if the necessary information is included in order toservice the request. In embodiments, the necessary information includesat least a source location, a source type, a destination location, and adestination type. The source type and destination type are each definedby at least one publishing variable. In embodiments, publishingvariables for media content can include, but are not limited to, thefile format, bit rate, communication protocol(s), physical medium,compression algorithm, digital rights management information, or anycombination thereof. In one embodiment, the information required forservicing the request includes at least a source location, a sourceformat, a source bit-rate, a destination location, a destination format,and a destination bit rate.

If the task manager 206 determines that the request information is notcomplete, the task manager 206 will fetch the necessary information asshown in steps 506 and 508. For example, if the source type or sourcelocation is not included in the request and the requested media contentis stored within the media transcoding engine 106, the task manager 206can consult the database 210 to find the necessary source information.Alternately, if the media content is stored externally with respect tothe media transcoding engine 106, the task manager 206 can perform anetwork request to fetch the necessary information from the contentprovider's web-site. For example, the task manager 206 can perform anHTTP request, an RTSP request, or a request using any other standardnetwork application protocol. Additionally, if the destination type isnot available, the task manager 206 can fetch the needed information byquerying the viewer client 102. As discussed above, in embodiments, theoptimal destination type for the destination location may be stored as a“cookie” on the viewer client 102, which may be accessed by the taskmanager 206.

At step 510, once the task manager 206 has the necessary information toservice the request, it then determines what tasks need to be executedin order to deliver the requested media content. The tasks include allthe steps necessary to deliver the requested media content, and mayinclude fetching the requested media content, transcoding the requestedmedia content from the source type into the destination type, andstreaming the transcoded media content to the viewer client 102. Oncethe task manager 206 has determined what tasks need to be executed, itthen interfaces with the resource manager 208 and instructs the resourcemanager 208 to execute the required tasks.

The resource manager 208 receives the instruction to execute therequired tasks from the task manager 206 and, at step 512, assigns eachtask to one or more machines within the machine farm 216. The resourcemanager 208 is programmed to achieve an efficient execution of tasks bythe available resources. In embodiments, the allocation of resources toa given task by the resource manager 208 is determined based on avariety of factors including, but not limited to, which machines supportthe necessary utilities for performing the required task, which machineshave available resources (for example, available CPU), and whichmachines can coordinate with each other to carry out the task whencoordination is required for execution. The resource manager 208 canalso be programmed to distribute tasks based on a variety of othercriteria including the avoidance of network congestion. For example, theresource manager 208 may be programmed to assign decompression andcompression tasks to the same machine in order to avoid the networkcongestion that may result from transmitting uncompressed data from onemachine to another within the internal network of the media transcodingengine 106.

In accordance with the present invention, the resource manager 208oversees tasks after they are assigned to make sure that they areproperly executed. The resource manager 208 oversees the execution ofassigned tasks by maintaining a list of all assigned tasks in thedatabase 210 and periodically communicating with the slave monitor ofeach machine running a given task in order to determine the status ofthe task.

In embodiments, the resource manager 208 periodically polls the slavemonitor of the machine to which the task has been assigned to determinethe status of the task. In alternate embodiments, the slave monitoritself sends periodic status messages to the resource manager 208,informing it of the status of an assigned task. The resource manager 208stores information that it receives from the slave monitors about thestatus of each task and each machine in the database in order to assistin its function of assigning and monitoring necessary tasks.

In an alternate embodiment of the present invention, the slave monitorsonly initiate tasks received from the resource manager 208, and thetasks themselves report directly to the resource manager 208 rather thanto the slave monitors.

The resource manager 208 monitors each assigned task in accordance witha fault tolerance routine that permits the resource manager 208 todetermine when a task has failed and to execute the necessary steps forcorrecting the problem and ensuring the delivery of the requested mediacontent. For example, if a machine to which a task has been assigneddoes not respond to a status query for a predetermined period of time,the resource manager 208 can be programmed to reassign the task to adifferent machine and re-boot the machine that is not responding.Additionally, where the failure of a task also results in the failure ofa chain of distributed dependent tasks, the resource manager 208 can beprogrammed to shut down all the dependent tasks and re-assign the entireset of tasks in order to ensure the delivery of the requested mediacontent. These examples are not limiting, and other fault toleranceschemes will be apparent to one of ordinary skill in the relevant artbased on the teachings contained herein, and the invention is directedto such other fault tolerance schemes.

In a further embodiment of the present invention, individual tasks areeach assigned a priority. The resource manager 208 monitors new tasksand when the priority of an existing task is lower than that of a newtask that needs to be assigned, the resource manager 208 will instructthe existing task to kill itself to accommodate the new higher-prioritytask. Alternately, the slave monitor can kill the existing task. Anexample of a low priority task includes the transcoding of media contentfor a viewer after the viewer has stopped viewing the requested content.

At step 514, after all the tasks have been assigned, the task manager206 constructs a reply to the initial request to access media contentreceived from the viewer client 102. The reply serves to redirect theviewer client 102 to a streaming server or proxy server from which therequested media content will ultimately be received by the viewer client102. In embodiments, the reply comprises an HTTP reply.

At steps 516-526,the machines within the machine farm 216 perform thesteps necessary to deliver the requested media content in accordancewith the assigned tasks received from the resource manager 208. Inembodiments of the present invention, the delivery of media content is apipelined process in which the fetching, transcoding and streaming ofdifferent portions of the same media content stream may occursimultaneously. The resource manager 208 arranges for the pipelining ofthese steps through resource allocation within the media transcodingengine 106. The pipelining of these steps results in a faster deliverytime for requested media by the media transcoding engine 106.

As shown at step 516, if the requested media content already resides inthe transcoded cache 212 transcoded into the appropriate destinationtype (e.g., the appropriate destination format and bit-rate or otherappropriate publishing variables), then the delivery of content isachieved by the streaming servers 222 at step 524, which stream thetranscoded media content to the viewer client 102 as described below.

If, however, the requested media content does not reside in thetranscoded cache 212 transcoded into the appropriate destination type,then one of the transmitter servers 220 within the machine farm 216begins fetching the requested media content as a data stream from thesource location as shown at step 518. As discussed above in regard toFIGS. 3 and 4, in embodiments of the invention, the requested mediacontent can initially either reside within the master archive 214 withinthe media transcoding engine 106, in an archive external to the mediatranscoding engine 106, or be received as a streaming feed directly fromthe content provider client 104.

Where the requested media content resides within the master archive 214,one of the transmitter servers 220 fetches the requested media contentover the internal network of the media transcoding engine 106.

Where the requested media content resides in an archive outside of themedia transcoding engine 106, one of the transmitter servers 220 usesthe access information provided during the publishing process to fetchthe requested media content. In embodiments, after the transmitterserver uses the access information to fetch the requested media content,the requested media content may be temporarily cached in the masterarchive 214, permitting expedited access to the media content whensubsequent requests for the same media content are received by the mediatranscoding engine 106.

Where the requested media content is a streaming feed directly from thecontent provider client 104, one of the transmitter servers 220 fetchesthe streaming data from the content provider Web server interface 204.Because embodiments of the present invention do not fetch and transcodethe streaming data until it is actually requested by a viewer,unnecessary transcoding of media content is thereby avoided.

As shown in step 520, after the transmitter server begins fetching therequested media content, if the source type is the same as thedestination type (e.g., the source format and bit rate is the same asthe destination format and bit-rate), then no transcoding is necessaryand the media content is transmitted to the streaming servers 222 assoon it is fetched. The streaming servers 222 then stream the content tothe viewer client 102 at step 524, as described below. However, if thesource type is not the same as the destination type, then one of thetranscoding servers 218 within the machine farm 216 will transcode themedia content from the source type to the destination type as shown instep 522. In accordance with the discussion in regard to step 512,above, the resource manager 208 assigns the transcoding task to atranscoder server that runs the necessary transcoder software forperforming the appropriate conversion of publishing variables. Inembodiments, the transcoding is carried out using one of a variety ofwell-known methods and for converting media content of one type toanother, including conventional codec routines for transcoding mediacontent. Further description of transcoding operation and examples areprovided below.

In embodiments, after the transcoding is complete, a copy of thetranscoded media content is temporarily stored in the transcoded cache212, permitting expedited delivery of the media content when subsequentrequests for the same media content transcoded into the same destinationtype are received by the media transcoding engine 106.

In step 524, one of the streaming servers 222 streams the media contentin the appropriate destination type to the viewer client 102 as soon asit is received from either a transcoder, a transmitter or the transcodedcache 212. In embodiments, the transcoded media content is streamed tothe viewer client 102 via an optional proxy server, as discussed abovein regard to FIG. 2. In further embodiments, either the streaming serveror the optional proxy server keep usage statistics pertaining to themedia content being delivered as well as the destination types in whichthe media content is being delivered that are used by the resourcemanager 208 for cache management purposes.

In embodiments, the protocol used for streaming media to the viewerclient and for streaming data between the transmitter servers 220,transcoder servers 218 and the streaming servers 222 is a standardprotocol for streaming media, such as RTSP. Alternately, a proprietaryprotocol defined over standard network protocols like TCP/UDP can beused. In further embodiments, different protocols may be used toaccommodate different network infrastructure needs. For example,protocols may be implemented that dynamically change according tonetwork traffic conditions. However, these examples are illustrative.The present invention is not intended to be limited to a specificcommunication protocol or application, and other proprietary ornon-proprietary network communication protocols and applications can beused.

At step 526, the viewer client 102 receives the streaming media contentfrom either the streaming server or the proxy server. At this point, theviewer client 102 plays the media content in accordance with thedestination type associated with the media player resident on the viewerclient 102. In alternate embodiments of the present invention, the mediacontent may be received and stored as a downloaded file on the viewerclient 102 for playing at a later time, or for transfer to an alternatemedia playing device.

After step 526, the flowchart 500 ends.

F. Further Transcoder Operation and Media Content Examples

As described above, media transcoding engine 106 includes one or moretranscoders 218. Transcoders 218 convert certain types of media content(referred to herein as a source type) to another type of media content(referred to herein as a destination type). Transcoding can involve anumber of different conversion operations. The particular conversionoperations used depend upon the media content and associated publishingvariables being converted. Publishing variables as used herein refers todifferent characteristics of media content.

According to the present invention, media content is digital data beingpublished over a network. In this case, publication refers to digitaldata which has been formatted for delivery over a network and forviewing by a destination media player. Publishing variables for mediacontent can include, but are not limited to, the file format, bit rate,communication protocol(s), physical medium, compression algorithm,and/or digital rights management information.

The digital data can be any type of file format including but notlimited to container formats, bitmap formats, video formats, audioformats, vector formats, metafile formats, scene formats, animationformats, multimedia formats, hybrid formats, hypertext and hypermediaformats, three-dimensional data (3D) formats, virtual reality modelinglanguage (VRML) formats, font formats (bitmap fonts, stroke fonts,spline-based outline fonts), page description language (PDL) formats,and any other type of graphics file format or other file format. Table 1lists examples of such file formats that can be used in embodiments ofthe present invention:

TABLE 1 Example File Formats Format Type ADOBE ILLUSTRATOR MetafileADOBE PHOTOSHOP Bitmap ATARI ST GRAPHICS FORMATS Bitmap and AnimationAUTOCAD DXF Vector AUTODESK 3D STUDIO Scene Description BDF BitmapBRL-CAD Other BUFR Other CALS RASTER Bitmap CGM Metafile CMU FORMATSMultimedia DKB Scene Description DORE RASTER FILE FORMAT Bitmap DPXBitmap DR. HALO Bitmap DVM MOVIE Animation ENCAPSULATED POSTSCRIPTMetafile (page description language) FACESAVER Bitmap FAX FORMATS BitmapFITS Other FLI Animation GEM RASTER Bitmap GEM VDI Metafile GIF BitmapGRASP Animation GRIB Other HARVARD GRAPHICS Metafile HIERARCHICAL DATAFORMAT Metafile IFF Bitmap IGES Other INSET PIX Bitmap INTEL DVIMultimedia JPEG FILE INTERCHANGE FORMAT Bitmap KODAK PHOTO CD BitmapKODAK YCC Bitmap LOTUS DIF Vector LOTUS PIC Vector LUMENA PAINT BitmapMACINTOSH PAINT Bitmap MACINTOSH PICT Metafile MICROSOFT PAINT BitmapMICROSOFT RIFF Multimedia MICROSOFT RTF Metafile MICROSOFT SYLK VectorMICROSOFT WINDOWS BITMAP Bitmap MICROSOFT WINDOWS METAFILE Metafile MIFFBitmap MPEG Other MTV Scene Description NAPLPS Metafile NFF SceneDescription OFF Scene Description OS/2 BITMAP Bitmap P3D SceneDescription PBM., PGM., PNM., and PPM. Bitmap PCX Bitmap PDS OtherPICTOR PC PAINT Bitmap PIXAR RIB Scene Description PLOT-10 Vector PNGBitmap POV Vector PRESENTATION MANAGER METAFILE Metafile PRT SceneDescription QRT Scene Description QUICK TIME Other RADIANCE SceneDescription RAYSHADE Scene Description RIX Bitmap RTRACE SceneDescription SAF Bitmap and other SENSE8 NFF Scene Description SGI IMAGEFILE FORMAT Bitmap SGI INVENTOR Scene Description SGI YAODL SceneDescription SGO Vector SPIFF Bitmap SUN ICON Bitmap SUN RASTER BitmapTDDD Vector and Animation TGA Bitmap TIFF Bitmap TTDDD Vector andAnimation URAY Scene Description UTAH RLE Bitmap VICAR2 Bitmap VIFFBitmap VIS-5D Vector VIVID AND BOB Scene Description WAVEFRONT OBJVector WAVEFRONT RLA Bitmap WORDPERFECT GRAPHICS METAFILE Metafile XBMBitmap XPM Bitmap XWD Bitmap ZBR Metafile

See, Murray and vanRyper, pp. 12-26. These examples are illustrative andnot intended to necessarily limit the present invention. Other fileformats (now known or developed in the future) can be used as would beapparent to a person skilled in the art given this description.

Even within the same file format, digital data can be compressedaccording to different compression algorithms. In a QUICK TIME formattedfile, for example, video can be compressed in accordance with H.263,CINEPAK, JPEG, QT ANIMATION, or QT VIDEO standards. As a furtherexample, in a WINDOWS MEDIA ASF formatted file, audio can be compressedin accordance with the MICROSOFT AUDIO FORMAT, ACELP, VOXWARE, or MP3standards. Compression algorithm choices can be made based onoptimization according to bit-rate choices, or according to the natureof the content. For example, video files in which little motion occurs(“talking heads”) and video files in which there is a substantial amountof motion (“high-motion” video) may each be more efficiently compressedusing different compression algorithms.

Within any one compression algorithm, there can be further variations.For example, files compressed according to the JPEG standard can beeither YUB-based or RGB-based.

In addition to the publishing variables set forth above, there are alsopublishing variables unique to video data and audio data.

Publishing variables for video data include the width and height of thevideo image in pixels as well as the frame rate of the video. Dependingon the bit-rate requirements and the nature of the data, differentsettings may be necessary in order to ensure the best picture quality.For example, some video may be better viewed at 15 frames per second at160×120 pixels, while some others may be better viewed at 5 frames persecond at 320×240 pixels, even at the same bit-rate. Where the bit-rateis 56K bps, picture quality becomes very limited, and it is almost neveroptimal to deliver video in 640×480 pixel resolution. Yet anotherpublishing variable for video data is the number of bits per component.

Publishing variables for audio data include the number of samples persecond, the number of channels (e.g., mono, stereo, 5-channel) and thesample size (8-bit, 16-bit, etc.). Different settings may be necessaryto ensure audio quality in light of a particular content type andbit-rate.

Publishing variables may also include the size of data packets beingsent and the choice of transmission protocol (e.g., TCP vs. UDP).

FIG. 6 shows an example transcoder 218 that transcodes on demand sourcetype media content 610 to destination type media content 650. Sourcetype media content 610 is digital data delivered over a network in oneor more packets. The digital data that forms source type media content610 is defined by one or more publishing variables. The publishingvariables as shown in FIG. 6 include one or more of the followingvariables: source file format, source bit rate, source physical medium,source communication protocol, source encoding, or any combinationthereof. Destination type media content 650 is digital data deliveredover a network in one or more packets to an end user that demands themedia content. The digital data that forms destination type mediacontent 650 is also defined by one or more publishing variables. Thepublishing variables as shown in FIG. 6 include one or more of thefollowing variables: destination file format, destination bit rate,destination physical medium, destination communication protocol,destination encoding, or any combination thereof.

FIG. 7 shows a table of an example implementation where one or moretranscoders 218 transcodes on demand from a source type media content710 to a first destination type 750. FIG. 7 also shows an exampleimplementation where one or more transcoders 218 transcodes on demandfrom a source type media content 710 to a second destination type 760.The source type media content 710 includes digital data publishedaccording to the following source publishing variables: namely, thephysical medium is a local disk, the communication protocol includes afile I/O, the file format is MP3 using MP3 encoding at a bit rate of 128kilobits per second (kbps). The first destination type media content 750includes digital data transcoded for publication according to thefollowing destination publishing variables: namely, the physical mediumis a packet-switched network (the Internet), the communication protocolincludes WINDOWS MEDIA STREAMING MMS protocol, the file format isWINDOWS MEDIA FILE, using MP3 encoding at a bit rate of 56 kbps. Thesecond destination type media content 760 includes digital datatranscoded for publication according to the following destinationpublishing variables: namely, the physical medium is a Wireless Network,the communication protocol includes HTTP, the file format is MP3including MP3 encoding at a bit rate of 12 kbps.

Other examples are shown in the following tables:

Tables 2-5 Example Transcoder Operations

TABLE 2 Publishing Variables Source Type Destination Type physicalmedium Disk Network communication protocol(s) File I/O RTSP containerformat MPEG1 QUICK TIME encoding MPEG1 SORENSON (video) QDESIGN (audio)bit rate 1.5 Mbps 300 kbps

TABLE 3 Publishing Variables Source Type Destination Type physicalmedium Wired Network Wireless Network communication protocol(s) HTTP MMScontainer format MPEG1 WINDOWS MEDIA encoding MPEG1 MPEG4 (video)MSAUDIO (audio) bit rate 1.5 Mbps 100 kbps

TABLE 4 Publishing Variables Source Type Destination Type physicalmedium Wired Network Wired Network communication protocol(s) HTTP RTSPcontainer format QUICK TIME REAL encoding H.263 REAL PROPRIETARY G2Video/Audio bit rate 56 kbps 56 kbps

TABLE 5 Publishing Variables Source Type Destination Type physicalmedium Disk Wireless Network communication protocol(s) File I/O HTTPcontainer format MPEG1 MP3 encoding MPEG1 audio only—MP3 bit rate 1.5Mbps 16 kbpsThese examples are illustrative and not intended to limit the presentinvention. Other types of on demand transcoding operations that areknown now or developed in the future can be used as would be apparent toa person skilled in the art given this description.G. Alternate Embodiments of the Present Invention

Example embodiments of the methods and systems of the present inventionhave been described herein. As noted elsewhere, these exampleembodiments have been described for illustrative purposes only, and arenot limiting. Alternate embodiments, differing slightly or substantiallyfrom those described herein, will be apparent to persons skilled in therelevant art based on the teachings contained herein. For example, oneskilled in the relevant art will appreciate that the transcoding systemand method of the present invention is not limited to the transcodingand delivery of media content alone, but also encompasses thetranscoding and delivery of information of all types, including, but notlimited to compressed files, electronic documents, HTML pages, XMLdocuments, and any other information that can be stored in a pluralityof formats and delivered electronically. Other alternate embodimentsinclude, but are not limited to, hardware, software, andsoftware/hardware implementations of the methods, systems, andcomponents of the invention. Such alternate embodiments fall within thescope and spirit of the present invention.

H. Conclusion

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedin the appended claims. Accordingly, the breadth and scope of thepresent invention should not be limited by any of the above-describedexemplary embodiments, but should be defined only in accordance with thefollowing claims and their equivalents.

1. A method for providing media content transcoding services,comprising: (a) fetching media content; (b) selecting one of a pluralityof transcoders for transcoding from a plurality of source types to aplurality of destination types, wherein said one transcoder is selectedbased at least on the destination type; (c) sending the media content tosaid selected transcoder; (d) transcoding the media content to thedestination type, thereby generating transcoded media content; and (e)transmitting said transcoded media content; and (f) wherein saidselected one of said plurality of transcoders for transcoding from asource type to a destination type which have different: (1) file formatsof the media content; (2) bit-rates of the media content; (3)communication protocols according to which the media content istransferred; (4) physical media on which the media content is stored;(5) encoding formats; (6) compression algorithms; (7) digital rightsmanagement information; or (8) combinations thereof.
 2. The method ofclaim 1, said source type and said destination type having differentfile formats.
 3. The method of claim 1, said source type and saiddestination type having different bit rates.
 4. The method of claim 1,said source type and said destination type having differentcommunication protocols.
 5. The method of claim 1, said source type andsaid destination type having different physical media on which saidmedia content is stored.
 6. The method of claim 1, said source type andsaid destination type having different encoding formats.
 7. The methodof claim 1, said source type and said destination type having differentcompression algorithms.
 8. A method for delivering media content over anetwork, comprising: (a) transcoding the media content to generate aplurality of copies of the media content, each of said plurality ofcopies having a different destination type or a different source type orboth; (b) storing said plurality of copies in a cache; (c) receivingrequests for the media content; and (d) selecting and delivering a copyof one of said plurality of copies in response to each of said requests,(e) wherein said different destination type or different source type orboth of said each of said plurality of copies having different: (1) fileformats of the media content; (2) bit-rates of the media content; (3)communication protocols according to which the media content istransferred; (4) physical media on which the media content is stored;(5) encoding formats; (6) compression algorithms; (7) digital rightsmanagement information; or (8) combinations thereof.
 9. The method ofclaim 8, said different destination type or different source type orboth of said each of said plurality of copies having different fileformats.
 10. The method of claim 8, said different destination type ordifferent source type or both of said each of said plurality of copiesfurther having different bit rates.
 11. The method of claim 8, saiddifferent destination type or different source type or both of said eachof said plurality of copies further having different communicationprotocols.
 12. The method of claim 8, said different destination type ordifferent source type or both of said each of said plurality of copiesfurther having different physical media on which said media content isstored.
 13. The method of claim 8, said different destination type ordifferent source type or both of said each of said plurality of copiesfurther having different encoding formats.
 14. The method of claim 8,said different destination type or different source type or both of saideach of said plurality of copies further having different compressionalgorithms.
 15. The method of claim 8, said different destination typeor different source type or both of said each of said plurality ofcopies further having different digital rights management information.16. A method for transcoding media content from a source type to adestination type, comprising the steps of: (a) receiving a request forthe media content; (b) fetching the media content; (c) selecting one ofa plurality of transcoders for transcoding from a plurality of sourcetypes to a plurality of destination types, wherein said one transcoderis selected based on the source type and the destination type; (d)sending the media content to said selected transcoder; (e) transcodingthe media content from the source type to the destination type, therebygenerating transcoded media content; (f) transmitting said transcodedmedia content; and wherein the source type and the destination type aredefined by at least digital rights management information.
 17. A methodfor providing media content transcoding services, comprising; (a)fetching media content; (b) selecting one of a plurality of transcodersfor transcoding from a plurality of source types to a plurality ofdestination types, wherein said one transcoder is selected based atleast on the destination type; (c) sending the media content to saidselected transcoder; (d) transcoding the media content to thedestination type, thereby generating transcoded media content; and (e)transmitting said transcoded media content; and (f) wherein saidselected one of said plurality of transcoders for transcoding from asource type to a destination type which have different digital rightsmanagement information.
 18. A method for delivering media content,comprising: (a) transcoding the media content to generate a plurality ofcopies of the media content, each of said plurality of copies having adifferent destination type or a different source type or both; (b)storing said plurality of copies in a cache; (c) receiving requests forthe media content; and (d) selecting and delivering a copy of one ofsaid plurality of copies in response to each of said requests; (e)wherein said different destination type or different source the or bothof said each of said plurality of copies having different digital rightsmanagement information.
 19. A method for providing media contenttranscoding services, comprising: (a) fetching media content; (b)selecting one of a plurality of transcoders for transcoding from aplurality of source types to a plurality of destination types, whereinsaid one transcoder is selected based at least on the destination type;(c) sending the media content to said selected transcoder; (d)transcoding the media content to the destination type, therebygenerating transcoded media content; and (e) transmitting saidtranscoded media content; and (f) wherein said selected one of saidplurality of transcoders for transcoding from a source type to adestination type which have different digital rights managementinformation.
 20. The method of claim 1, said source type and saiddestination type having different digital rights management information.